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Explicitly creates a collection. create has the following form:

  create: <collection_name>,
  capped: <true|false>,
  autoIndexId: <true|false>,
  size: <max_size>,
  max: <max_documents>,
  flags: <0|1|2|3>,
  storageEngine: <document>

create has the following fields:

Field Type Description
create string The name of the new collection.
capped boolean Optional. To create a capped collection, specify true. If you specify true, you must also set a maximum size in the size field.
autoIndexId boolean

Optional. Specify false to disable the automatic creation of an index on the _id field.


For replica sets, all collections must have autoIndexId set to true.

size integer Optional. Specify a maximum size in bytes for a capped collection. Once a capped collection reaches its maximum size, MongoDB removes the older documents to make space for the new documents. The size field is required for capped collections and ignored for other collections.
max integer Optional. The maximum number of documents allowed in the capped collection. The size limit takes precedence over this limit. If a capped collection reaches the size limit before it reaches the maximum number of documents, MongoDB removes old documents. If you prefer to use the max limit, ensure that the size limit, which is required for a capped collection, is sufficient to contain the maximum number of documents.
flags integer

Optional. Available for the MMAPv1 storage engine only to set the usePowerOf2Sizes and the noPadding flags. To set, specify one of the following values:


MongoDB 3.0 ignores the usePowerOf2Sizes flag. See collMod and db.createCollection() for more information.

Defaults to 1.

New in version 2.6.

Changed in version 3.0.0: Add support for setting the new noPadding flag.


Do not set noPadding if the workload includes removes or any updates that may cause documents to grow. For more information, see No Padding Allocation Strategy.

storageEngine document

Optional. Available for the WiredTiger storage engine only.

New in version 3.0.

Allows users to specify configuration to the storage engine on a per-collection basis when creating a collection. The value of the storageEngine option should take the following form:

{ <storage-engine-name>: <options> }

Storage engine configuration specified when creating collections are validated and logged to the oplog during replication to support replica sets with members that use different storage engines.

The db.createCollection() method wraps the create command.


The create command obtains a write lock on the affected database and will block other operations until it has completed. The write lock for this operation is typically short lived. However, allocations for large capped collections may take longer.


Create a Capped Collection

To create a capped collection limited to 64 kilobytes, issue the command in the following form:

db.runCommand( { create: "collection", capped: true, size: 64 * 1024 } )

Specify Storage Engine Options

New in version 3.0.

You can specify collection-specific storage engine configuration options when you create a collection with db.createCollection(). Consider the following operation:

db.runCommand( {
    create: "users",
    storageEngine: { wiredTiger: { configString: "<option>=<setting>" } }
} )

This operation creates a new collection named users with a specific configuration string that MongoDB will pass to the wiredTiger storage engine. See the WiredTiger documentation of collection level options for specific wiredTiger options.

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